Current-collecting apparatus for dynamo-electric machines.



J. E. HOEGGEBATH. cmmn' consume APPARATUS r01: zmmlo BLBO'I'RIO 1110mm.

APPLIUATIOI'I FILED OUT. 10, 1906.

904,801. Patented Nov. 24, 1908.

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JAKOB NOEGGERATH, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC UNITED STATES PATENT OFFICE.

COMPANY, A CORPORATION OF NEW YORK.

CURRENT-COLLECTING APPARATUS FOR DYNAMO-ELECTRIC MAGEENES.

Specification of Letters Patent.

Application filed October 10. 1906-. Serial No. 338,257.

Schenectady, county of Schenectady, State l of New York, have invented certain new and useful Improvements in Current-Collecting Apparatus for Dynamo-Electric Machines, of which the following is as ecification.

, My invention relates to ynamo-electric machines and more particularly to brushes and supports therefor, and has for its object to improve the same.

The various features of my invention will he pointed outwith particularity in the appended claims'; but fora full understanding of my invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawing.

a In said drawing, l igure 1 is a side elevation of a brush and brush-holder arranged in accordance-with the present invention, the brush bearing upon a collector ring; Fig. 2- is a plan view of the parts shown in Fig. 1, a portion of the brushholder stud broken away s w its construction; and Fig. 3 is an enlarged longitudinal section of one end of the briish.

'30 In dynamo-electric machines having ourrent collectors which run at high peripheral speeds the brushes wear away rapidly, and in high speed unipolar machines, whose collector rings have peripheral speeds much higher than in other types of machines, the wearing of the brushes presents a serious problem. In one of its aspects my inven-' tion relates to means for overcoming this objectionable wear upon brushes.

I have found that there is no appreciable wear in a brush either when there is no current flowing'through it, or when there is no relative m -vement between the brush and the collectprs; but when both of these conditions are present, wear takes place, and in increased ratio as either the current or the relative movement increases.

B my invention the brush is so constructed that the portion thereof which takes the" wear carries but little current while the portion through which the current flows is subjected to but little wearing influence. 'This may conveniently besaccomplished by building up the brush of strips or laminations, certain of the strips ter-ia to more clearly with the rush ad acent the outer beingstren drawing, where A is a'brush being made up of thin strips or bundles of strips 1,-.p'referably of copper or bronze, alternatingwith strips 2, of iron or other materialhavinga-p considerably lower conductivity than the-- copper. 3, 3, 3, are stifi'ening stripsfwhich may be added where it is desired to have the U Patented Nov. 24, 1 908..-

composed of a good conducting ma-w and others having a lowerconductivity and preferably a higher mechanical I l; gth. Such a brush is illustrated in the brush stifi'er than would be the case if the lector ring upon which the brush bears.

.In operation, the current density in. the strips 2 is quite low strips 1. Therefore, thetendencyt of the strips 2 to wear away is small; and, since it is impossible for the copper or bronze strips to wear away at a, faster rate, the brush as a whole wears but slowly, even for Very high peripheral speeds of the collector ring.

a brush-holder which may be advan Bis strips 1 and '2 alone were used. a his a col-8,,

tageously used with brushes of the character described. This brush holderconsists 'ofa member 5 adapted to be clamped upon the; brush-holder stud 6 in any suitablemanner, as by means of a set screw 7 passing through ears 8 and 9 on the member. 1 J

10 is the brush receiving memben journaled on the brush-holder stud by means of earsall and 12 which, when the parts are assembled, are positioned on opposite sides of the member 5. On the member 10v is a brush guide 13 through which the brush passes and in which it is adjustably secured by means of may be forced against the collector ring with any desired degree of pressure by means of a thumb-screw 15 carried by an arm 16 on themember 10, and bearing at one end upon an arm 17 projecting from the member 5, and therefore fixed with respect to the stud.

18 is a spring arranged on the up er side 100 of the brush and intended particu arly to effect the proper pressure between the extreme outer end of the brush and collector ring. This spring may conveniently be substantially U-shaped tl rtinn or its length, one arm thereof bearmg upon the top of the brush, but being preferabl bent upward out of engagement end thereof, as at 19, and then engaging a thumb-screw 14:. The brush iroughout the major the brush but it Ishigh 1n the v,

again at the extreme outer end 20. The end of the other arm of the spring is adapted to bear upon the bow-shaped portion 19 of the companion arm, whereby a stiff spring action is obtained at the extreme outer end of the brush. The tension of the spring may be adjusted by, means of wing nuts 21. screw-threaded upon theshat't of the thumb screw 14, and bearing upon the outer side of the upper arm of thesprihgl In placing the parts in, position, the arm of the spring which bears upon .the brush is preferably placed in position in the brush guide 13, together with he brush, so as to he looked in position at the same time, and by the same means as the brush itself. Thus, it will be seen thatthe brush as a whole "may be adjusted so as to vary the pressure betwe n it and the collector ring, and a further independent adjustnicnt atthe ,tip of the brush may be obtained by means of the spring The brush holder stud 6 illustrated, is

adapted to support two brush nolders ditt'ering in potential and consistsof a member 22 having a socket, and a member 23 having a tenon adapted to enter the socket and leave sufficient space for the substantial sleeve of insulation 2-1 between the two members; By making the tenon sufficiently long, a very ri id two-part stud, the ends of which are e ectively insulated from each other. may be obtained.

that I claim as new and desire to secure by Letters Patent of the United Statesais- 1. In a dynamo-electric machine, a. col lector rin arranged to operate at ahigh periphera speed, and a brush engaging sari t ring, said brush being composed of stifi'enin ieces and thin strips of material having high conductivity, alternating with thin stri s having low conductivity and greater mec anical strength than the other strips, one of said sti'tfening pieces being placed on h -4 l-lu: thin strips,

2. In a dynamoelectrio machine. a collector ring arranged to operate at ahigh peripheral speed, and a brush engaging said ring, said bruslrbeing composed of stiffening pieces and thin strips of material having high conductivity, alternating with thin strips having low conductivity and greater mechanical strength than the other strips, one ofsaid stiffening pieces being placed on each side of the thin strips and one stiffening piece substantially in the middle of the thin strips.

3. In a dynamo-electric machine, a current collector, a longitudinally laminated brush ,en a ging said collector, a brush holder, and a siibstantially U-shaped spring on said brush holder, one arm of said Ubearing upon the top of said brush throughout the.

major portion of its length and having a bow-shapcdportion engaging the brush adjacent the outer end thereof. 1

t. In a dynamo-electric machine, a current collector, a lpngitudinall -laminated brush engaging said collector, a rush holder, at substantially U-sha ed spring on said holder one arm of sai U bearing upon the top of said brush throughout the rumor portion of its length, and having a bow-shaped portion engaging the brush adjacent the outer end thereof, the other arm of, the U being adapted to bear upon portlon of said first arm, and means for ad- ]usting the tension of said spring.

A brush holder stud consisting of a member having a socket, a member having a projection entered into said socket, and insulation between said members.

In witness whereof, I have hereunto set my hand this 9th day of ()ctober, 1906.

J AKOB E. NOEGGERATH.

\Vituesses:

BEN AMIN B. HULL, HELEN ORFORD.

the bow'shaped 

